DESCRIPTION: This proposal is driven by the hypothesis that regional specification of the forebrain is largely controlled by a hierarchy of genes encoding transcriptional regulators. A large portion of the proposal depends on gene knockout technology which will be used to inactivate the Dlx-1 and Dlx-2 genes, both individually and simultaneously. The phenotype of mice that are heterozygous and homozygous for the mutations will be analyzed histologically and biochemically.